Why did my gold fish attack the others?

Just purchased and prepared a 10 gallon tank for 3 gold fish for my children. I really out of my way to make sure the tank was suitable. Then 1 of the goldfish attacked the other two and bit the fins off of one! What could be the cause of this?

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  • Anonymous
    6 months ago
    Favorite Answer

    Never mind asking why. It's too late now because the other fish are damaged and they're probably going to slowly die. But when you put a new fish in a tank you need to keep an eye on it. And if it turns out it's an aggressive fish it's better to scoop it out with a net and toss it to your cat. Better one fish should die then all the other fishes that you paid a bunch of money for should die.

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  • Edwena
    Lv 7
    6 months ago

    We have a goldfish pond and the fish lived peacefully in it for years. Then the 6 largest fish squared off for a death battle. No known cause, but it might have something to do with breeding. Each fish got into a corner during the day to defend itself, then at night, they would battle. Ripped fins, bruised, eyes out. Then back into the corner during the day. This battle went on for about 4 days until only one fish was alive and it died from the wounds. I have asked lots of people about this, and never got an answer. Your question is the first about a similar incident ,i.e a death fight among goldfish. Totally bizarre behavior for a goldfish. The strange thing is that the smaller fish, a couple just slightly smaller, did not participate in the fight, and continued to live peacefully in the pond for years afterwards. Gold fish males will kill a female during breeding using similar tactics of chasing her and shredding her fins, and bumping her which will kill her. But it is not a fight, per se.

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    • Edwena
      Lv 7
      6 months agoReport

      I did not know the sex of a particular fish, but I think it was both sexes. I am pretty sure it was not an animal since the pond is deep with vertical sides and hiding places. No history of predators. So cranes and raccoons cannot fish it.

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  • 6 months ago

    10 gallons is too small for goldfish, which can lead to aggression. Or a misidentified species.

    I would swap them for White Cloud Mountain minnows.

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  • Anonymous
    6 months ago

    "really out of my way to make sure the tank was suitable. "

    No, no you didn't.

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  • Raven
    Lv 5
    6 months ago

    Breeding, possibly? That sucks though, wow.

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